Circular burner for the vacuum-tight pinching of light sources having quartz tubes

ABSTRACT

A circular burner for pinching the quartz tube bulb of light sources having an internal diameter 1.2 to 1.6 times the diameter of the quartz tube to be pinched, and in which the volume ratio of the mixing chamber to that of the outlet channels amounts to 1:8 to 1:16, preferably 1:10 to 1:12. The burner according to the invention has in the interior a circularly shaped body provided with approximately semicircular form milled recessed burner inlets arranged along the periphery with uniformly distributed bores parallel to the axis of the burner. The burner is of such design that the inlet rings, and comb plates placed between them and provided with outlet openings, form a cylinder jacket. The burner is terminated both on the top and bottom by closing-up plates equipped with conduits for circulating a cooling fluid, preferably water.

UnitedStates Patent 1191 Geiszler, deceased et a1.

CIRCULAR BURNER FOR THE VACUUM-TIGHT PINCHING OF LIGHT SOURCES HAVING QUARTZ TUBES Inventors: Lorine Geiszler, deceased, late of Budapest, Hungary by Henriette Geiszler, heiress; Tibor Simon, Goedalso; Mihaly Varga; Agoston Tolnay, both of Budapest, all of Hungary Assignee: Egyesutt lzzolampa es Villamossagi Reszenytarsasag, Budapest, Hungary Filed: June 13, 1973 Appl. No.: 369,721

US. Cl 239/l32.3, 239/557, 239/566 Int. Cl B05b 15/00, B05b 1/06, BOSb 1/14 Field of Search 239/430, 433, 552, 556, 239/557, 566, 567, 592, 128, 132, 132.1, 132.3

References Cited UNITED STATES PATENTS 8/1941 Hughey 23 /552 9/1945 Scherl 239/566 X A circular burner for pinching the quartz tube bulb of Oct. 22, 1974 2,438,170 3/1948 Hughey 239/552 2,745,476 5/1956 T811 23 1/5157 x 2,768,635 10/1956 Redmond 239/567 ux 3,372,916 3/1968 P1656611 ct 111 239/567 x Primary Examiner-Robert S. Ward, Jr.

ABSTRACT light sources having an internal diameter 1.2 to 1.6 times the diameter of the quartz tube to be pinched, and in which the volume ratio of the mixing chamber to that of the outlet channels amounts to 1:8 to 1:16, preferably 1:10 to 1:l2. The burner according to the invention has in the interior a circularly shaped body provided with approximately semicircular form milled recessed burner inlets arranged along the periphery with uniformly distributed bores parallel to the axis of the burner. The burner is of such design that the inlet rings, and comb plates placed between them and provided with outlet openings, form a cylinder jacket. The burner is terminated both on the top and bottom by closing-up plates equipped with conduits for circulating a cooling fluid, preferably water.

6 Claims; 4 Drawing Figures l CIRCULAR BURNER FOR THE VACUUM-TIGHT PINCHING OF LIGHT SOURCES HAVING QUARTZ TUBES The vacuumtight and bubblefree closing-up of these quartz tube bulbs, (the so-called pinching) poses a very difficult problem.

Accordingly, pinching is extensively performed with hand operated machines. For heating quartz tubes up to a plastic state, which is an essential part of the closing-up operation, there are used two or four part flat burners which distribute heat evenly along a circle, thus uniformly heating the tube. Trials have already been carried out for developing automatic quartz tube pinching machines, with the object of increasing the productivity by mechanizing the operations formerly carried out by hand production. On these machines different forms of multipart burners are used. While, however, with hand operated machines with low performances (30 to 50 pieces per hour), this arrangement of burners is acceptable, in the case of automatic pinching by machines and higher productivity (400 to 600 pieces per hour) it is unsuitable for solving the problem, because uniform heat distribution in the quartz body cannot be achieved by it.

In addition, a further inconvenience of the multiburner arrangement is that the grate flame dispersion damages surrounding component parts, and that for the elimination of this disadvantage the design of a more complicated machine would be needed. Attempts have been made with circular burners, too; this, however, had as its object only the elimination of SiO particles deposited on the quartz tube, and required a significantly lower temperature than that of about 2,000 C needed for pinching.

The mechanizing of pinching has been impeded up to now by having to produce a high power burner, suitable to produce good quality pinching.

Such a burner should meet the following requirements:

From the point of view of pinching, the quartz tube should be heated decidedly to a plastic state, and

a. first of all uniform and quick heating of the quartz tube end to 2,000 C should be ensured;

b. at the same time the current leads, and electrode armature parts should be protected from oxidation; and

c. the softened quartz tube must not be twisted away from its axis.

The present invention has among its objects the realization of a burner meeting the above requirements, and eliminating the inconvenience of hitherto known burners and making the automation of pinching possible.

The invention relates to a circular burner for pinching the quartz tube bulb of light sources, characterized by having an internal diameter 1.2 to 1.6 times the diameter of the quartz tube to be pinched, and in which 2 t the volume ratio of the mixing room to that of the outlet channels amounts to 1:8 to 1:116, preferably 1:10 to 1:12.

. In the burner according to the invention, in the interior there is a circular, (or in other designs two semicircularly shaped) milled recess provided with approximately burner inlets arranged along the periphery with uniformly distributed bores parallel to the axis of the burner.

The burnerr is of such design that the inlet rings and comb plates places between them provided with outlet I openings form a cylinder jacket. The burner is terminated both on the top and bottom by closing-up plates equipped with conduits for circulating a cooling fluid, preferably water. I

By varying the number of the inlet rings and comb plates the cylinder jacketmay be varied corresponding to the height of the tube part to be pinched.

In one construction the burner :is divided, e.g. forming two burner parts of semi-circular form.

In a further construction, the outlet openings of the comb plates are uniformly distributed.

The invention will be explained in detail in connection with the accompanying drawing showing one exemplified embodiment of a burner inlet and of the burner, according to the invention.

'In the drawing:

FIG. 1 in a top view of a divided burner inlet;

FIG. 1a in a section of a burner inlet half according to FIG. 1;

FIG. 2 is a view in elevation of a divided burner; and

FIG. 3 is a top view of the burner half shown in FIG. 2.

The burner shown has a semi-circular inlet ring 1. This is-shown in FIGS. 1 and 2, in FIG. la in detail in section. Inlet ring 1 is provided on both sides with semicircular or nearly semicircular milled recesses 13. Inlet ring 1 is also provided parallel to its axis with uniformly distibuted bores 14. This design has the advantage of ensuring uniform outlet pressure and by it also symmetrical circular heating. At the same time, as shown in FIGS. 2 and 3, introduction of gas is asymmetrical so as not to introduce gas with locally higher pressure.

The ratio of the mixing chamber and of the channel volumes enables the burner to be extinguished or newly fired during working without risking back-firing, and at the same time makes it insensitive to pressure variations of the gas mixture.

The burner according to the invention may be operated by oxygenated town gas, hydrogen, or by an arbitrary mixture of propane-butane gas. It is thus from this point of view also advantageous by not requiring the use of a special fuel, since it operates safely and serviceably with any gaseous fuel.

In FIG. 2 it can be seen that comb plates 2 provided with outlet openings 3 are placed between the inlet rings 1 of semicircular form. Screws 9 serve to the out let rings 1 and comb plates 2. Covering plates 15 closeup the top and the bottom of the burner body. The flame reaches the quartz tube to be pinched through outlet openings 3, the tube being accommodated in the burner by surrounding it in form of a cylinder jacket. For clarity of illustration the quartz tube to be pinched is not shown.

Outlet-openings 3 are uniformly distributed in the comb plates 2 in order to reach the quartz tube by a flame whichis as uniform as possible.

The gas mixture passes through inlet openings 4 to tubes 7 and thence to the outlet openings 3, where it is ignited and heats the quartz tube to be pinched. The cooling fluid, which is preferably water, passes the circular burner through inlet openings 5, tube 8, and by conduits 11 and 12, and then passing through tube leaves at outlet opening 6. All such conduits are connected to covers 15. Good cooling is very important, since in its absence the burner, operating at a high temperature, would be damaged. The two burner halves, as can be seen in the drawings, totally surround the quartz tube to be pinched. The number of inlet rings 1 and of comb plates 2 may be varied according to the length of the zone of the quartz tube to be pinched which is to be heated. The gas mixture with the purpose of feeding the burner, may be as mentioned already before an oxygenated mixture of town gas, hydrogen or propane-butane.

The burner according to the invention has the following advantages:

The burner surrounds the quartz tube to be heated in the form of a cylinder jacket; it is unimportant whether the burner is made in the form of a closed ring or as two half-rings to be opened and closed. The quartz tube is heated uniformly at any point, and unevennesses in dimensions and quality are equalized to a great part. The quartz tube may be heated to a plastic state in a socalled closed shell with optimal velocity (350 C/s), held in the center without twisting. The inlets may be partially closed by valves (not shown) to ensure uniform outgoing gas pressure and by this a symmetrical circular, heating. By the proper choice of the internal dimensions of the burner corresponding to a quartz tube of given dimensions, heating is effected very concentratedly, and the required temperature may be reached in a much shorter time than with hitherto known burners. Furthermore, no SiO deposition occurs with the use of the burner of the invention.

It also follows from the concentrated heating that machine parts in-the vicinity of the burner are not damaged, and also that the oxidation of current-leading electrodes by stray flames is eliminated.

Since the burner surrounds the softening quartz tube like a room of circular cross section and the flame pressure is symmetrical in the room, and since the quartz tube remains throughout the heating in the center line of the flame room, no twisting of the quartz tube oc- Although the invention is illustrated and described with reference to a plurality of preferred embodiments thereof, it is to be expressly understood that it is in no way limited to the disclosure of such a plurality of preferred embodiments, but is capable of numerous modifications within the scope of the appended claims.

What is claimed is:

1. A circular burner for pinching quartz tube bulbs of light sources, comprising a burner body having an internal diameter 1. 2 to 1.6 times the diameter of the quartz tube to be pinched, cylinder jacket constituted by comb plates provided with outlet openings and placed between inlet rings, the jacket being equipped on both ends with cooling fluid circulating covering plates, the volume ratio of the mixing chamber of the burner to the outlet channels being in the range 1:8 to 1:16.

2. A circular burner according to claim 1, wherein the volume of the mixing chamber to the outlet channel lies in the range 1:10 to 1:12.

3. A circular burner according to claim 1, wherein ing the number of the inlet rings and of the comb plates.

5. A circular burner according to claim 1, wherein the burner is made of a plurality of burner parts.

6. A circular burner according to claim 1, having further evenly distributed outlet openings on the comb 

1. A circular burner for pinching quartz tube bulbs of light sources, comprising a burner body having an internal diameter
 1. 2 to 1.6 times the diameter of the quartz tube to be pinched, cylinder jacket constituted by comb plates provided with outlet openings and placed between inlet rings, the jacket being equipped on both ends with cooling fluid circulating covering plates, the volume ratio of the mixing chamber of the burner to the outlet channels being in the range 1:8 to 1:16.
 2. A circular burner according to claim 1, wherein the volume of the mixing chamber to the outlet channel lies in the range 1:10 to 1:12.
 3. A circular burner according to claim 1, wherein the burner has several circularly shaped burner inlets provided with semicircular recesses and provided with evenly distributed bores along the periphery parallel to the burner axis.
 4. A circular burner according to claim 1, wherein the height of the cylinder jacket may be varied by varying the number of the inlet rings and of the cOmb plates.
 5. A circular burner according to claim 1, wherein the burner is made of a plurality of burner parts.
 6. A circular burner according to claim 1, having further evenly distributed outlet openings on the comb plates. 